1. Field of the Invention.
This invention relates in general to air bearing sliders for use with recording media and more particularly, to a slider having air bearing surface features which minimize contamination sensitivity.
2. Description of Related Art.
A magnetic storage device typically comprises one or more magnetic disks, each having at least one data recording surface including a plurality of concentric tracks of magnetically stored data, means such as a spindle motor for supporting and rotating the disk(s), at least one read/write transducer per recording surface for reading information from and writing information to the recording surface, an air bearing slider for supporting the transducer over the recording surface, and means such as an actuator/suspension assembly for selectively positioning the transducer and slider over a desired data track.
As is generally known in the art, airflow enters the slider's leading edge and flows in the direction of its trailing edge, generating a lifting force or "positive pressure" on the slider's air bearing surface (ABS), thereby supporting the slider at a nominal fly height over the recording surface.
As is also known in the art, numerous air bearing designs exist to achieve particular fly height characteristics. Many of these designs include air bearing designs that provide openings to the incoming airflow. A problem with such designs occurs when debris enters these openings and accumulates on the air bearing surface. Particles may occur, for example, during the manufacture or assembly of the disk drive, from moving parts that wear over a period of time, a faulty air filtering system, or slider contact with disk asperities. If the particles are small, they will merely pass beneath the air bearing surface unobstructed. However, larger particles of debris will accumulate, for example, by encountering obstructing features such as crossrails. As a result, the debris buildup can affect the fly height sensitivity of the slider, scratch the recording surface, damage the delicate transducer or interfere with the transducer's operation.
A number of design approaches have been taken to deal with surface debris. For example, U.S. Pat. No. 4,212,044 discloses a positive pressure slider with an air bearing surface comprising a pair of side rails and a plurality of shaped diverter blades at the trailing edge and parallel to the incoming airflow. The diverter blades force small particles of dust to either side, preventing the accumulation of dust along the trailing edge. However, this design will not prevent larger particles from accumulating along the air bearing surface.
U.S. Pat. No. 5,210,666 discloses a negative pressure slider with a notch formed in its tapered cross-rail, functioning in part to minimize debris collection at the slider's leading edge. Rather than preventing particles from passing beneath the air bearing surface, this design permits relatively small particles to pass under the air bearing surface so that they do not accumulate at the leading edge.
As is generally known in the art, a negative pressure slider design includes a region for generating a suction force to counteract and stabilize the positive pressure on the air bearing surface. Japanese application no. 4-228157 discloses a negative pressure slider having two T-shaped rails defining a negative pressure cavity with a shallow groove opening to the leading edge. The groove provides a channel for debris so that it does pass beneath the slider and therefore does not accumulate along the leading edge. However, this channel affects the negative pressure created by the negative pressure cavity thereby affecting the fly height of the slider.
I.B.M. Technical Disclosure Bulletin Vol. 35, No. 7, page 14, December 1992 discloses a slider for use in a rotary actuator disk drive, including a skewed rail for sweeping aside particles on the disk surface. This design is useful for pushing aside particles too large to pass beneath the slider air bearing surface, but would not prevent all large particles from lodging between the slider and recording surface or from accumulating along the crossbar.
As a result of debris buildup in the crossbar area, air bearing surface (ABS) designs lose fly height. This has been observed in sliders from file testing as well as in component particle injection testing.
It can be seen then that there is a need to prevent debris from collecting in the crossbar region.
It can also be seen then that there is a need for a slider air bearing surface design which significantly reduces the fly height sensitivity to contamination in the crossbar area.
It can also be seen that there is a need for a method of making a slider air bearing surface design with significantly reduced fly height sensitivity to contamination in the crossbar area.